Jet compressor for power plants



April 1942- G. w. PEARCEHJR 2,280,447

JET COMPRESSOR FOR A POWER PLANT Filed Oct. 13, 1939 2 Sheets-Sheet l April 1942- (5. vii. PEARCE, JR I 2,280,447 IJET'COMPRESSOR FOR A POWER PLANT J Filed Oct. 15, 1939 Z'Sheets-Sheet 2v Patented Apr. 21, 1942 1 UNITE-D snares PATENT OFFICE 1 7 2,280,447

JET COMPRESSOR FOR POWER PLANTS George W. Pearce, Jr., Pittsburgh, Pa. Application October 13, 1939, Serial No. 299,300 I 6;Claims.

This invention relates to a method and apparatus for doing work, more particularly by a heat engine using gas as a working, medium and referred to herein as a power ,plant.

It-is among the objects of this invention to provide such a powerplant which is highly efflcient and economical in operatiomand which is extremely simple in construction; .Other objects are to provide a method for efiiciently and economically introducing a fluid into a fluid system.

In accordance with this invention an injector forms a major feature of my power plant and comprises a mixing chamber and a jet. The jet is connected with the chamber, and thelatter is provided with an outlet and with an additional inlet that is adapted to be connected with the atmosphere or to any source of fluid under a pressure less than that of the gas supplied to the jet. If the additional or second inlet of the mixing clia-mberis connected to a fluid at subatmospheric pressure, the inlet of the jet may be open to the atmosphere because the air will flow through'the jet to the lower pressure zone in the mixing chamber. On the other hand, the inlet of the jet may be connected to a source of gas under pressure. In either case, as the gas flows through the jet it expands to a lower pressure and resion starts is lowered by-a suitable cooling me dium before or during compression of the mixture, Wherefore less energy is required to handle a unit weight of the second fluid drawn into the injector, and more of it can be handled by a given amount of the actuating gas. Likewise, if the temperature of the actuating gas after expansion is above that of the second fluid, and the kinetic energy in the warm gas after expansion be transferred to a cool intermediate fluid which is used to aspirate the second fluid, less energy is required to handle 'a given amount of the second fluid. Thus, in both cases less of the heat in the actuating gas remains in the compressed gases delivered by the injector than in a conventional injector. Therefore, the compression of the gases accompanied by .a smaller temperature rise, and more of the second fiuid can be compressed than heretofore. I

In one of the manyforms that this invention may take, the second inlet of the mixing chamber can be connected to a receptacle from which it is'desired to remove a fluid. Or, this invention may be used to mix a plurality of fluids in which it is desired to; have the resulting mixture at a pressure higher thanv could be obtained heretofore without cooling ,of the higher pressuregas after its expansion starts. In still another form of the invention this inlet may be ing drawings in which Fig. 1 is a diagrammatic view of my power plant connectedto a turbine; Fig. 2 is a fragmentary diagrammatic view of a modified embodiment; and Fig. 3 is a view similar to Fig. 1 showing the power plant used for withdrawing a fluid from a receptacle. 0

Referring to Fig.1 of the drawings, a combustion-chamber I isprovided near its bottom with an outlet 2 to which an injector is connected. The injectorcomprises a jet 3 leading fromoutlet 2 to a mixing chamber 4; having a second inlet 6 open to the atmosphere and having an outlet oppositethejet through which a delivery tube 1 extends. The combustion chamber is also provided with an inlet 8 through which air is introduced into the chamber wherein its temperature and pressure are raised. The heating of the air may be doneby heating-the chamber from the outside, or by introducing a suitable iuelwith the air, such' asthrough a fuel pipe 9 adjacent inlet 8', and igniting the combustible mixtureby a spark plug ll mounted in the-wall of the chamber. After the combustion chamber wall reaches incandescence, burning will cona tinue Without the spark plug. To initially compress the gas'in the combustion chamber to the desired pressure, inlet 8'is connected by a pipe i2;

and valve 13 to an .Qrdinaryair compressor l4 driven in any suitablemanner. It is a featu'reof this invention that after the apparatus has been started in operation valve l3 may be closed and the compressor turned off, thereby saving the power required to operate the compressor. Thecombustion and pressure in the combustion chamberare maintained by only, a-

portion .of oxygen-containing gases that leave mixing chamber 4 and which are returned to the combustion chamber in a. manner about to be h described. The rest of those gases are used, in this embodiment, to operate a turbine. In order to accomplish these novel results, means is provided for cooling the hot gases from the combustion chamber after expansion starts in the jet and before recompression in the delivery tube ceases so that the recompression will be accompanied by a smaller temperature rise than otherwise. Although this cooling may be done in various ways, it is preferred to do it by placing a cooling liquid, such as water, in direct contact with the hot gases as they leave the jet. For this purpose a nozzle l6 encircles the jet and is connected by a pipe I! to a water storage tank I8. To separate the water from the gases after the cooling operation has been completed, a separating tank I9 is connected to the outlet of delivery tube l. The water that settles to the bottom of this tank is led back to the water storage tank through a pipe 2| that is so formed as to cool the water flowing through it. The pressure of the gases above the-water in the separating tank forces the water through thepipes and storage tank to nozzle I6. Water that is lost in the system with the gases may be replaced through a supply pipe 22 connected to the storage tank.

The kinetic energy resulting from the expansion of a gas in a jet is sufficient to recompress it to substantially its original pressure and temperature. However, due to the cooling of the hot gases by the cooling liquid in accordance with this invention, the recompression starts in the delivery tube at a lower temperature than that at which expansion normally would have ceased, and consequently the gases are recompressed to substantially their original pressure at a much lower temperature and with a smaller temperature rise. Due to the recompression thus taking place in a lower and smaller temperature range, it requires less kinetic energy to recompress the gases than was released during their'expansion. The excess energy delivers the air drawn in from the atmosphere through auxiliary inlet 6 of the mixing chamber against the higher pressure of the gases in the separating chamber. Consequently, more gas is recompressed than left the combustion chamber through the jet. A sufficient amount of this gas, containing oxygen, is conducted from the separating tank through a return pipe 23 to inlet 8 of the combustion chamber to support combustion in the latter and to maintain the desired pressure therein without the further use of air compressor l4. The-remainder of the gas, which is substantially equivalent to the volume of air drawn into the mixing chamber from the atmosphere, is led out of return pipe 23 through a pipe 24 to a turbine 26 which it operates in the usual manner.

Between pipes I2 and 24, return pipe 23 is provided with a valve 21 that is closed while the com pressor is operating so that it will pump air into the combustion chamber only. Turbine pipe 24 is provided with a throttling valve 28 which is adjusted to permit only gas in excess of theamount needed for the combustion chamber to be supplied to the turbine.

The apparatus shown in Fig. 2 has been modified to provide means for separating the products of combustion from the cooling or intermediate liquid before they reach the mixing chamber so that only the intermediate liquid passes into that chamber. Accordingly, jet 3 and the spray nozzle [6 are connected to the main inlet of the mixing chamber by a conduit 3| having a second outlet 32 near the mixing chamber. As the expanded gases and the liquid from nozzle [6 pass through this conduit, the gases separate from the liquid and pass out through outlet 32 to the atmosphere or to any other suitableplace. However, the kinetic energy produced by the expanded gases is transferred to the liquid which passes on to the mixing chamber and draws the second fluid in through inlet 6. If inlet 6 is open to the atmosphere the fluid that reaches separating tank I 9 is composed largely of the liquid from nozzle l6 and air.

The power plant illustrated in Fig. 3 is used for withdrawing a fluid from a receptacle rather'than for driving a turbine or the like. In this embodiment the second or auxiliary inlet 6 of mixing chamber 4 is connected through a valve 4| to a receptacle 42 from which it is desired to remove a fluid, This may be for the purpose of transferring the fluid to another receptacle or for creating a vacuum in receptacle 42. To operate this apparatus valve l3 connecting compressor pipe 12 with inlet pip 8 is opened, and a valve 43 in a pipe 44 that connects inlet pipe 8 with the atmosphere is closed. The compressor is set in operation in order to build up suflicient pressure in combustion chamber l to cause the gases issuing from jet 3 to expand to a pressure below that of the fluid in receptacle 42. The compressor continues in operation until the gases issuing from the jet have withdrawn suflicient fluid from receptacle 42 to reduce its pressure below atmospheric. Valve l3 may then be closed and valve 43 opened because the products of combustion from the combustion chamber will continue to flow to the lower pressure area in the mixing chamber and thus continue to reduce the pressure in receptacle 42.

' In order that there will be sufiicient energy in the mixing chamber to recompress the gases issuing therefrom through delivery tube 1 to atmospheric pressure or to the pressure of whatever receptacle may be connected to the tube, the gases issuing from the jet must be cooled after expansion starts and before recompression ceases. Although this cooling may be effected in the same Way as shown in Fig. 1, another method of cooling is shown in Fig. 3. This consists of providing the delivery tube with means, such as cooling fins 46, for dissipating the heat from the gases flowing therethrough, I

Although this invention has been described in connection with a single stage injector, it will be understood that the same principles are equally applicable to multistage injectors. I a

Accordingto the provisions of the patent statutes, I have explained the principle and method of practicing my invention and have illustrated and describedwhatI now consider to represent its best embodiments. However, I desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described. I

I claim; I q

1. In a power plant, the combination comprising a heating chamber member for heating gases therein, an outlet jet connected to said chamber for expanding the heated gases to increase their kinetic energy, a mixing chamberconnected to the jet'for receiving the expanded gases and provided with an opening through which a gas is drawn by said gases and mixed therewith, a gradually expanding delivery tube connected to the mixingchamber for receiving allof the gases therefrom and in which "said kinetic energy is used to compress the mixture of gases, means for restricting the temperature rise of said mixture during said compression whereby said kinetic energy is sufficient to compress the mixture to a pressure greater than that of the gases in the heating chamber, and a conduit member for conducting enough of said compressed mixture back to the heating chamber member to replace the gases escaping through the jet, one of said members being provided with an outlet for the rest of said compressed mixture so that power can be furnished thereby.

2. In a power plant, the combination comprising a heating chamber member for heating gases therein, an outlet jet connected to said chamber for expanding the heated gases to increase their kinetic energy, a mixing chamber connected to the jet for receiving the expanded gases and provided with an opening through which a gas is drawn by said gases and mixed therewith, a gradually expanding delivery tube connected to the mixing chamber for receiving all of the gases therefrom and in which said kinetic energy is used to compress the mixture of gases, means for cooling said gases after expansion starts whereby said kinetic energy is sufficient to compress the mixture to a pressure greater than that of the gases in the heating chamber, and a conduit member for conducting enough of said compressed mixture back to the heating chamber member to replace the gases escaping through the jet, one of said members being provided with an outlet for the rest of said compressed mixture adapted to be connected to a gas-operated device ior actuating it.

3. In a power plant, the combination comprising a heating chamber member for heating gases therein, an outlet jet connected to said chamber for expanding the heated gases to increase their kinetic energy, a mixing chamber connected. to the jet for receiving the expanded gases and provided with an opening through which a gas is drawn by said gases and mixed therewith, a gradually expanding delivery tube connected to the mixing chamber for receiving all of the gases therefrom and in which said kinetic energy is used to compress the mixture of gases, means for cooling said gases with a liquid after expansion starts whereby said kinetic energy is sufiicient to compress the mixture to a pressure greater than that of the gases in the heating chamber, means for separating the liquid from said vided with an opening through which a gas is drawn by said gases and mixed therewith, a gradually expanding delivery tube connected to the mixing chamber for receiving all of the gases therefrom and in which said kinetic energy is used to compress the mixture of gases, means for introducing a liquid into said gases to cool them after expansion starts and before compression ceases whereby said mixture is compressed to a pressure greater than that of the gases in the heating chamber, a separating tank member connected to the outlet of the delivery tube for separating the liquid from said mixture, and a conduit member connecting said tank memher with said heating chamber member for conducting enough of said compressed mixture back to the heating chamber member to replace the gases escaping through the jet, one of said members being provided with an outlet for the rest of said compressed mixture so that power can be furnished thereby.

5. In a power plant, the combination comprising a heating chamber member for heating gases therein, means for initially pumping air into the chamber, an outlet jet connected to said chamber for expanding the heated gases to increase their kinetic energy, a mixing chamber connected to the jet for receiving the expanded gases and provided with an opening through which a gas is drawn by said gases and mixed therewith, a

gradually expanding delivery tube connected to,

the mixing chamber for receiving all of the gases therefrom and in which said kinetic energy is used to compress the mixture of gases, means for restricting the temperature rise of said mixture during said compression whereby said kinetic energy is sufficient to compress the mixture to a pressure greater than that of the gases in the heating chamber, and a conduit member for conducting enough of said compressed mixture back to the heating chamber member to replace the gases escaping through the jet, one of said members being provided with an outlet for the rest of said compressed mixture so that power can be furnished thereby, and means for stoppin said air pumping means as soon as enough of said compressed mixture is conducted by said conduit back to the heating chamber to replace said escaping gases.

6. I'he method of obtaining power from a combustible fuel, comprising burning the fuel under pressure, expanding the gaseous products of com bustion in a jet to increase their kinetic energy, entraining air in the expanded gases, using said kinetic energy to compress the mixture of gases and air, restricting the temperature rise of said mixture during said compression whereby said kinetic energy is sufiicient to compress the mixture to a pressure greater than that of said fuel under pressure, returning a portion of said mix ture to said fuel under pressure to supply thereto the oxygen for combustion, and bleeding off the rest of said mixture to be used as power.

GEORGE W. PEARCE, J R. 

